Studies on production of resistant variant of Japanese pear 'Osa Nijisseiki' to Alternaria alternata Japanese pear pathotype by means of somatic mutation.

1.研究了建立高增殖率再分化体系所需的组织培养条件。以日本梨‘欧沙二世’的茎尖、茎、叶面和叶柄为材料。考察了无机营养物、植物生长调节剂、添加剂和胶凝剂的种类和浓度。茎尖生长出新芽，其他材料发育成愈伤组织。以茎尖愈伤组织为材料，考察了愈伤组织形成的条件。愈伤组织在WP无机营养物组成的培养基上增殖旺盛。虽然研究了各种植物生长调节剂和添加剂的使用，但未获得愈伤组织的再分化。以‘长竹’和‘小井’的茎尖为外植体，并以‘Osa nijisisiki’为外植体。通过将生长素、赤霉素和细胞分裂素与WP培养基结合，在‘Chojuro’中形成了许多不定芽。…更多为准备抗性变异的选育，从‘Osa nijisisiki’中提取的一株日本梨花交替病菌（Alternaria alternata Japanese pear）从单个孢子中分离得到一株表现出高孢子形成能力和高产毒能力的菌株，并进行了孢子增殖。一株对日本梨也有毒性的草莓互花孢病菌在证实其孢子形成能力后进行了增殖。这些孢子被冷冻保存在超低温冰箱里。本研究获得了许多关于‘蛇麻’组织培养的新信息。然而，由于没有建立大规模繁殖所需的培养条件，我们没有成功地生产出耐黑斑病的变体。然而，在‘Chojuro’中，建立了一个足以产生多个芽的培养条件。这一结果表明，利用类似的系统进行多芽繁殖，可以选育出耐黑斑病的‘Ose nijisisiki’梨变种。少

1.The tissue culture conditions necessary for the establishment of a re-differentiation system with a high rate of multiplication were investigated. The shoot apex, stem, lamina, and petiole of the Japanese pear 'Osa Nijisseiki' were used as a material. Types and concentrations of inorganic nutrients, plant growth regulators, additives, and gelling agents were examined. The shoot apex grew shoots, while other materials developed calli. The culture conditions necessary for the establishment of calliclones were examined by using the callus derived from the shoot apex. The calli proliferated vigorously on the medium composed of WP inorganic nutrients. Although the use of various plant growth regulators and additives was examined, re-differentiation from the callus was not obtained.The shoot apexes of 'Chojuro' and 'Kosui' in addition to 'Osa Nijisseiki' were used as explants. Many adventitious buds were formed in 'Chojuro' by combining auxin, gibberellin, and cytokinin with the WP medium. … More 2.As preparation for the selection of a resistance variant, a Alternaria alternata Japanese pear pathotype extracted from 'Osa Nijisseiki' was isolated from a single spore, a strain expressing a high spore formation ability and high toxin producing ability was screened, and the spore was then proliferated. A Alternaria alternata strawberry pathotype which also shows toxicity to the Japanese pear was proliferated after confirmation of its spore formation ability. These spores were freeze preserved in a super-low-temperature freezer.Much new information regarding the tissue culture of 'Osa Nijisseiki' was gained from this study. However, we did not succeed in producing a black spot tolerance variant since the culture conditions necessary for mass propagation were not established. However, in 'Chojuro', a culture condition sufficient for multiple shoot production was established. This result suggests the possibility of selecting a 'Ose Nijisseiki' pear variant with black spot tolerance by producing multiple shoots using a similar system. Less